The instant invention relates to a process for the replacement of full bobbins on a spinning/spooling machine in which the supplied yarn is wound up into a bobbin by means of a traverse yarn guide moving in a bobbin winding zone, and in which it is clamped and cut off in a clamping and cutting zone at the side of, and next to, the bobbin support after the replacement of a full bobbin by an empty bobbin support. The invention further relates to a device to carry out the process.
To carry out bobbin replacement, proposals have been made in the past to reduce the operating speed of the spinning machine, to stop the yarn guide in its left end position and to press an empty bobbin support or tube inserted into a bobbin tube holder, against the winding shaft after ejection of the full bobbin from the bobbin carrier, said bobbin tube or support having first been brought into immediate proximity of the full bobbin by swiveling the bobbin holder (see German Patent Publication DE-OS 2.503.545). The yarn is then pressed by a yarn deflection plate against the left face of the bobbin support where it comes into range of a knife and where it is clamped between the bobbin support plate and the bobbin support or tube as the bobbin carrier closes. The rotation of the bobbin tube finally causes the yarn segment connecting the bobbin tube to the replaced, full bobbin to be severed at the knife.
A disadvantage of this process is that it is unsuitable for high bobbin speeds and is, furthermore, only applicable when all the bobbins of the machine are being replaced at the same time.
According to another known device, the yarn, which is continuously supplied by the device, is cut above the draw-off rollers before bobbin replacement and is introduced into a swiveling nozzle, the swiveling motion of which causes the yarn to reach the gap between the bobbin support and the centering head of the bobbin holder after the replacement of the full bobbin by an empty bobbin tube or support and while the bobbin holder is not yet completely closed (see German Publication DE-OS 2.312.609). At that point, or inside the centering head itself, the yarn is clamped as the bobbin holder closes and is cut by scissors attached at the outlet of the swiveling nozzle. To provide a yarn reserve on the bobbin tube or support, the yarn is held at a distance from the area of the yarn guide by a guiding wire. Once the yarn reserve has been provided next to the actual bobbin winding, the yarn is pressed down by the guide wire so that it can be caught by the traverse yarn guide and can be wound appropriately on the bobbin body.
This handling of the yarn is not suitable for high machine speeds when there is a danger that the yarn might not be caught by the yarn guide.